Uglify-es is no longer maintained

[realityking]

Apologies if this has already been discussed, I haven't found an issue for it.

uglify-es is no longer maintained. @alexlamsl has stated a couple of times that it's "is no longer maintained and will not receive any bug fixes or new features",

Source: mishoo/UglifyJS#3067 (comment), mishoo/UglifyJS#2979 (comment)

uglify-es is already 15 bugfix released behind.

[alexander-akait]

@realityking #262

[realityking]

Poor search skills, my bad.